WASHINGTON — There’s a ghost haunting Elizabeth Warren as she ramps up for a possible 2020 presidential bid and a reelection campaign in Massachusetts this year: her enduring and undocumented claims of Native American ancestry.

Warren says now, as she has from the first days of her public life, that she based her assertions on family lore, on her reasonable trust in what she was told about her ancestry as a child. . .

But that self-awareness may not be enough, as her political ambitions blossom. . . there’s also discomfort on the left and among some tribal leaders and activists that Warren has a political blind spot when it comes to the murkiness surrounding her story of her heritage, which blew up as an issue in her victorious 2012 Massachusetts Senate race. In recent months, Daily Show host Trevor Noah mocked her for claiming Native American ancestry and the liberal website ThinkProgress published a scathing criticism of her by a Cherokee activist who said she should apologize.

As Warren is mentioned as a serious presidential contender in 2020, even some who should be her natural allies say Warren has displayed a stubborn unwillingness to address the gap between the story she was told of Native Americans in the family tree and a dearth of hard evidence to back it up.

It’s a disconnect that has lingered unresolved in the public sphere for more than five years. . .

Some tribe members want her to apologize to Native Americans for claiming heritage without solid evidence. Tribes across America have spent centuries denouncing whites who claim Indian DNA without a clear basis, claims they find deeply offensive. . . [S]ome Native American leaders are resentful that she’s done, in their estimation, little to help tribes as a powerful senator. . . “She’s not part of the Cherokee community,” said Chad Smith, who was the principal chief of the Oklahoma-based Cherokee Nation from 1999 to 2011.